Problem: Write the following expression in its most factored form: $9x+15$
To factor a polynomial, you should first try to find the greatest common factor of all the terms. The factors of $9x$ are $1$ $3$ $9$ , and $x$ and the factors of $15$ are $1$ $3$ $5$ , and $15$ The greatest common factor of $9x$ and $15$ is $3$ We can factor out the $3$ and put it before the parenthesis. If we divide each of the terms in the original expression by $3$ we get $\dfrac{9x}{3} = 3x$ and $\dfrac{15}{3} = 5$ So the factored expression is $3(3x + 5)$.